THE DEVELOPMENT OF ALGORITHMS FOR ON-DEMAND 
MAP EDITING FOR INTERNET AND MOBILE USERS WITH GML AND SVG 
Miss. Ida K.L CHEUNG “, Mr. Geoffrey Y.K. SHEA" 
* Department of Land Surveying & Geo-Informatics, The Hong 
Kong Polytechnic University, Hung Hom, Kowloon, Hong Kong, 
email: ida.cheung@polyu.edu.hk 
? Department of Land Surveying & Geo-Inforn 
jatics, The Hong Kong Polytechnic University, Hung Hom, Kowloon, Hong Kong, 
email: geoffrey.shea(gpolyu.edu.hk 
Commission VI, PS WG IV/2 
KEY WORDS: Spatial Information Sciences, GIS, Research, Internet, Interoperability 
ABSTRACT: 
The widespread availability of the World Wide Web has led to a rapid increase in the amount of data accessing, sharing and 
disseminating that gives the opportunities for delivering ma 
many vendors or companies have produced their own web map products w 
data formats without standardization. Such problem has long been an issue. 
XML grammar written in XML Schema for the modelling, transport, and storage of 
al and non-spatial properties of geographic features. GML is developed by Open GIS 
designed to provide solutions. GML is an 
geographic information including both spati 
ps over the Internet as well as small mobile devices. In GIS industry, 
hich have their own version, data model and proprietary 
Therefore, Geographic Markup Language (GML) was 
Consortium in order to promote spatial data interoperability and open standard. 
Since GML is still a newly developed standard, this promising research field provides a stan 
mapping information in terms of data modelling, spatial data representation mechanism and 
dardized method to integrate web-based 
graphic presentation. As GML is not for 
data display, SVG is an ideal vector graphic for displaying geographic data. GML sets at the back-end to store and transport data 
meanwhile SVG sets on front-end to render and display geographic data. The technology does not onl 
geographic data on the web, but also gives the possibility to e 
environment in which GML gives a significant improvement of bandwidth, speed, 
y enable the visualization of 
dit geographic data online, especially via Internet and wireless 
access and reliability. Since both GML and SVG 
is text-based and vector format, it is expected that downloads can be considerably shortened and even more important for bandwidth 
can be substantially improved. 
This paper therefore seeks to investigate the capability of GML and develop a corresponding data modelling, system and prototype 
in order to overcome or improve the existing limitation on GIS functions. Further discussion also emphasizes on online map editing 
function which is still not well developed over existing web mapping system. 
1. INTRODUCTION 
The widespread availability of World Wide Web gives the 
opportunities for delivering maps over the Internet as well as 
small mobile devices. The sharing of spatial data through 
Internet is important to promote interoperability of spatial data. 
Interoperability implies that there is some common concept on 
which information exchange and integration is based. 
(Vckovski, 1999) 
Currently, there were over 30 different Web mapping software 
packages or solutions provided by different GIS vendors. Most 
popular Web Mapping packages are ESRI ArcIMS, Autodesk 
MapGuide, GeoMedia WebMap server, and MapInfo 
MapXtreme (Peng, Z. R. and Tsou, M. H., 2003). They all have 
their own proprietary data formats and different customized 
programming languages. Some of them render images such as 
GIF and JPEG but these raster data cannot be selected, changed 
styling or zoomed in for more detail. In term of vector data, 
different data formats restrict the integration of data for 
applications and analyses. Moreover, different data formats 
support different spatial models. For instance, a particular GIS 
format support complex spatial model whereas another merely 
support simple feature model. It is difficult to share data 
between disparate Internet systems over a wide area network. 
On application level, the proprietary Web mapping applications 
are limited to their own corporate networks and developing 
languages. The vendor-based on-line spatial services and clients 
means that systems are neither interoperating with systems on 
the data level, nor the application level. 
On functional level, most Web mapping software packages can 
perform simple GIS functions such as zooming, querying, 
selecting, buffering and styling. They seldom perform more 
advanced GIS functions such as spatial analysis and spatial 
editing. In existing market, two Web mapping software 
packages, ArcIMS and Autodesk MapGuide, offer GIS 
functions which are closed to editing capability on spatial data. 
The ArcIMS Java Viewer using feature services has two 
functions called MapNotes and EditNotes. The MapNotes 
function enables users to add text or graphics to the map. These 
edits are then sent to the MapNotes folder on the ArcIMS 
Server. The EditNotes function enables users to edit features on 
the displayed map. Similar to MapNotes, once users finish 
editing, the changes will be submitted to the EditNotes folder 
on the ArcIMS Server for the server administrator to review. 
EditNotes must be converted to shapefiles or XML. MapNotes 
and EditNotes are therefore just graphics on map but not edited 
features on the server (Alex, F., 2002). 
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